Back-hitch gaintry



G. C. NOLL ETAL.

BACK- June 4, 1963 HITCH GAN'IRY 3 Sheets-Sheet 1 Filed April 14, 1961INVENTORS PAUL E. WESEBAUM 8 GEORGE C. NOLL 011mm. mm; Dummy ATTORNEYSJ1me 1963 e. c. NOLL ETAL 3,092,250

BACK-HITCH GANTRY Filed April 14, 1961 3 Sheets-Sheet 2 FIG 2 IN VENTORS PAUL E. WESEBAUM 8 BY GEORGE C. NOLL ohmnmh nmu ATTORNEYS n 9 3 G.c. NOLL ETAL 3,

BACK-HITCH GANTRY Filed April 14, 1961 3 Sheets-Sheet 3 64 63 8Q 43 8244 42 2 8| .5 1r 8 83E, 84

INVENTORS PAUL E. WESEBAUM 8u 'n FIG 5 BY GEORGE c NOLL Y3 DormzuqATTORNEYS United States atent O 3,092,260 BACK-HITCH GANTRY I George C.Noll and Paul E. Wesebanm, Elyrra, Oh o, assignors to The Thew ShovelCompany, Loraln, Ohio, a corporation of Ohio Filed Apr. 14, 1961, Ser.No. 103,045 4 Claims. (Cl. 212-59) This invention relates, as indicated,to a back-hitch gantry and more particularly to a retractible gantry forpower cranes, shovels, and the like.

In such power cranes and shovels, a boom is employed which is generallyraised and lowered by means of a boom hoist cable trained about a seriesof sheaves anchored at a point on the crane or shovel cab. It is, ofcourse, desirable to have this anchor point as high as possible on thecab frame to obtain as great an angle as possible between the hoistcable and the crane or shovel boom. It will, of course, be understoodthat the greater the angle, the higher the lifting capacity.

At the present time, it is a prevalent practice to mount power cranes onwheeled carriers for highway travel and for added mobility in movingfrom one place to another and if the anchor point for the boom hoistcable sheaves is as high as desired to obtain the required liftingcapacity, or indeed, to raise the boom from horizontal position, suchpresents an obstruction in that the crane cannot readily pass underbridges, power lines or the like when it is being transported overhighways. Fixed mast structures for the sheave anchors have beenprovided, but these are impractical and undesirable since it is requiredto remove entirely or dismount such anchor before the crane can betransported. Even in retractible masts, such as that disclosed in theEkbom et a1. Patent 2,348,285, it is necessary for the operator to leavethe cab or employ a second person to retract the cable anchor to thetravelling position of the crane.

It is accordingly a principal object of the present invention to providea back-hitch gantry which can be raised or lowered by the operatorwithout leaving his seat within the crane cab.

It is another important object to provide a retractible gantry for acrane, shovel, and the like which will provide maximum liftingcapacities and clearance heights in its extended and retracted positionsrespectively.

It is a further important object to provide a back-hitch gantry ofsimplified construction which can automatically be raised and lowered bythe crane operator and which will be completely safe and certain inoperation.

It is yet another object to provide a power driven crane or shovelwherein the aforesaid back-hitch gantry will permit maximum operatormaneuverability.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andthe annexed drawings setting forth in detail certain illustrativeembodiments of the invention, these being indicative, however, of but afew of the various ways in which the principles of the invention may beemployed.

In said annexed drawings:

FIG. 1 is a side elevation view of a crane in accordance with thepresent invention showing the back-hitch gantry in its raised (in solidlines) and lowered (in phantom lines) positions;

FIG. 2 is a top plan view of the crane of FIG. 1 with the carrierremoved for clarity of illustration showing the back-hitch gantry in itsretracted or lowered position;

ice

FIG. 3 is an end elevation partially broken away on a somewhat enlargedscale of the back of the crane showing the back struts only with theback-hitch gantry in its elevated position;

FIG. 4 is a fragmentary sectional view taken substantially on the line44 of FIG. 3;

FIG. 5 is a fragmentary detail View of the mechanism within theoperators cab employed to operate the gantry; and

FIG. 6 is a fragmentary detail view of the locking pin structure as seenfrom the right in FIG. 4.

Referring now to the drawings and more particularly to FIG. 1, there isillustrated a power driven crane mounted on a crane carrier with thelongitudinal axis of the carrier being shown at right angles to thelongitudinal axis of the boom of the crane. The crane carrier chassis 1is power driven and has thereon a turntable 2 which rotatably mounts thecrane 3 on the carrier. The carrier chassis 1 is provided with groundengaging wheels 4 and Power- Se outn'ggers 5, Power-Set being theregistered trademark of The Thew Shovel Company of Lorain, Ohio.Reference may be had to the copending application of Spencer Bowman,Serial No. 803,597, filed April 2, 1959, now Patent No. 3,021,015,entitled Outriggers for Power Shovels, Cranes, or the Like, for a morecomplete description of Outriggers that may be employed with cranes ofthis type. It will, of course, however, be understood that anyconventional beam type outrigger may be employed with the presentinvention.

The crane cab 6 is mounted on a turntable bed and A-frame 7 with the cabhousing an internal combustion engine or the like generally shown at 8to drive hoisting drums '9 with the hoisting cable 10 extending aboutsheave 11 mounted on axle '12 at the peak of the A-firame. A removablecounterweight 13 is fastened to one end of the bed and A-frameremov-ably held by means of turnbuckles '14 depending from L-shape framesupport members 15. At the opposite end of the turntable bed there ispivoted at 16 the crane boom shown generally at 17. The crane boom hasvfour square section tubular cords 18 which may be interconnected bytubular lacing members 19 welded to the inside faces thereof. Referencemay be had to the copending application or" Erwin Brekelbaum et 211.,Serial No. 548,512, filed November 22, 1955, entitled Tubular Boom, fora more complete disclosure of a crane boom that may be employed with thepresent invention. However, the crane and boom structures form no partof the present invention.

As seen perhaps more clearly in FIG. 2, the boom peak is provided with atransversely extending shaft 20 to which boom pendants 21 and 22 aresecured by means of the cable links 23 and 24. It will, of course, beunderstood that the shaft 20 will be provided with central sheaves forthe bucket or book cables or the like and such, of course, forms no partof the present invention. As shown, the pendants 21 and 22 are connectedthrough the pin connections 25 and 26 to right and left hand pendantlinks 27 and 28 to harness shaft 29 which has rotatably mounted thereonfour sheaves 30 31, 32 and 33 with boom hoisting cable 10 trainedthereabout. The shape of the links 27 and 28 can be more clearly seen inFIG. 1 and such protect the hoisting cable and sheaves as the harness islowered onto the boom when the cable is slackened. Collars 34 and 35 areprovided on the floating harness shaft 29 to hold the sheaves withminimum clearance.

The aforedescribed harness will be referred to generally as floatingharness 36 and it will be seen that the boom hoist cable 10 is alsotrained about sheaves in a further harness generally shown at 40. Thisharness 40 is mounted for movement on the distal end of upper gantryframe 3 41. Such upper gantry frame comprises side struts 42 and 43 seeFIG. 2) and the proximal end of such frame is pivoted to the gantryhinge pin shaft 44-. The harness axle or shaft 45 extends through thedistal ends of struts 42 and Mounted at the opposite ends of the shaft45 are boom hoist cable sheaves 46 and 47. A padlock type harness 48 issecured to the shaft 45 and mounts sheaves 49 and 50 therein forrotation about axes normal to the .axis of the shaft 45.

. It can now be seen that the boom hoist cable 10 is wrapped around thehoist'drurn 9 and extends over the sheave 11 or axle 12 fixed to the topof the A-frame. The cable 10 then passes about sheave 30 on axle 29 ofthe floating harness 36, about sheave 46 on axle 45, about sheave 31 onaxle 29, around sheaves. 49.and 50 in the padlock harness 48, about thesheave 32 in harness 36, about sheave 47 on axle 45, about sheave 33 inharness 36 and finally, such cable 10 is secured to the axle 12 at thetop of the A-frame as shown at 51. By reeling in the cable 1 on the drum9 or conversely paying the cable' out from the drum, the distancebetween harnesses 36'and 40 can be lengthened or shortened thus to loweror raise boom 17. The lifting force will then substanthe line drawn fromsuch shaft to the hinge pin 44 of the backhitch gantry shown generallyat 60. However, when the boom is nearly horizontal, the side struts 42and 43 rest on the axle 12 and a slight angle will be formed between thependants and the side struts.

The back-hitch gantry, which derives its name from being hitched overthe back of the cab or turntable as opposed to masts secured to thefront of the turntable tially always be exerted on the boom peak shaft20 along shapes as will be required to provide the necessary strengthand rigidity in the frame 61.

Referring now more particularly to FIGS. 1 and 3, the telescoping backframe member 62 is comprised of two parallel telescoping struts 70 and71. The struts are gen erally identical in form and only the struts 70will be described in detail. The strut 70 includes a top strut member 72which fits between spaced parallel lower struts 73 and 74. Transverseguide plates 75 and 76 are secured to the edges of struts 73 and 74 atthe top thereof holding them in the proper spaced parallel position. Thestrut 72 has similar plates in the form of flanges 77 and 78 on thelower end thereof which serve to cooperate with plates 75 and 76 toguide and maintain the strut 72 properly aligned and Within the struts73 and 74. The parallel struts 73 and 74 are anchored by the pin 79adiacent the top of the removable counterweight 13'. In

A spacer collar 82 is provided with thrust washers separating thevarious frame connections. Bushings will be employed to provide theproper rotation of the frame members about the hinge pin 44. Lookingcollars 83- and 84 will be'employed on the hinge pin 44 properly to holdthe assembly together.

The mechanism for operating the telescoping gantry comprises atransversely extending lock pin operating rod arms 101 and 102 locked tothe rod '89.

.and 104 in the uppenmost strut members 72.

89 mounted between extensions 90 of the members 75 on the top of thelowermost struts73, 74 (see particularly FIGS. 3, 4 and 6). An operatingcable 91 is secured to the locking pin operating rod 89' as shown at 92and a spring 93 is employed extending between the lower strut member 74and collar 94 secured to the rod 89. The cable 91 is mounted forlongitudinal reciprocation in a cable conduit 95 which passes throughgrommet 96 into the operators cab to be operated by the controlmechanism shown more clearly in FIG. 5 which will be placed just to theleft rear of the operators seat. The cable mechanism which takes a formsimilar to that of a Bowden wire can then be employed to reciprocate thelocking pin operating rod,89, a pull on the cable 91 moving the rod 89'to the left as seen in FIG. 3v against the pressure of spring 93.Locking pins 97 and 98 are mounted within collars 99 and 100 with suchpins being secured to The collars 99 and 100 guide the pins 97 and 98for longitudinal movement into and out of spaced locking pin holes 10-3A stop collar 195 may be secured to the end of the operating rod 89 tolimit the axial movement thereof caused by the movement of operatingcable 91. It can now be seen that a longitudinal pull on the cable 91will cause the operating rod 89 to move to the left in FIG. 3compressing spring 93 and moving the locking pins 97 and 98'simultaneously out of the holes 103 or 1014 in the upper strut members72 of the telescoping struts 70 and 71 of the back-hitch gantry.

Referring now to FIG. 5, the operating mechanism for the cable 91comprises a lever pivoted at 111 to a .cable mounting bracket 112secured to the roof or the like 113 of the crane cab. The cable 91 issecured to an offset portion 114 of lever 110 by means of a yoke and pinconnection shown generally at 115. A cable guide 1 16 is mounted on thebracket 112 permitting longitudinal movement of the cable therethrough.In order to exert a longitudinal force on the pull cable 91 to cause thespring 93- to compress, the lever 1-10 is pulled downwardly to thedotted line position shown at 117.

Here, the pin connection 115 will-be below the pivot 111 to provide aself-locking toggle mechanism in which the force of spring 93 willmaintain the lever 110 in its lowermost position. A suitable stop 118may be provided to keep the lever 110 from pivoting in a' furthercounter clockwise direction than that shown.

i Operation In order to raise the gantry, the boom 17 is lowered to theground or suitable cribbing and the derricking cable 10 is slacked off.In such lowered position, it will, of course, be understood that thelocking pins 97 and 98 would be engaged within the apertures 104 in thetop struts 72. The pins 97 and 98 are released by swinging the lever110, in the operators cab or enclosure to the dash line position of FIG.5. Then by taking up on the boom derricking cable 10, the gantry wouldbe raised,

this pivoting frame 61 about axle 12. It is understood that the freeweight of the boom will be sufiicient to cause the gantry automaticallyto extend. The locking pin lever 110 may be released from its lockedposition as soon as the gantry has been raised approximately 3 or 4inches. This will allow the spring 93 to hold the locking pins 97 and98; against the sides of the upper gantry struts 72.

' 97-and 98 in the holes 103-. The operator can then douif the gantrydoes not start to collapse, he will know that the pins are in properengagement.

In order to lower the retractible gantry, the boom 17 is again loweredto the ground or placed on cribbing and tension is maintained on theboom hoist derricking cable after the boom is lowered. The locking pins97 and 98 are released by swinging the lever 110 in the operators cab tothe dotted line position and the gantry is then lowered by paying outthe cable 10 from drums 9. The lever 116 may be released from itsself-locking position after the gantry has been lowered approximately 3or 4 inches and the spring 93 will then hold the pins 97 and 98 inspring pressed engagement against the sides of the upper struts 72 ofthe telescoping back struts 7! and 71. The operator then continues toslack ofr on the derricking cable until the pins 97 and 98 snap intoapertures 1114 and, at this time, the lever 111} will be swung back byspring 93 to the full line position to indicate to the operator that thepins 97 and 93 are properly engaged in holes 104. After the gantry islowered, in order to double check the proper engagement of the pinswithin such apertures 104, the operator need only raise the boomslightly. It is noted that in the collapsed or retracted position of thegantry, shown in phantom lines in FIG. 1 and in full lines in FIG. 2,the upper gantry frame 41 nests within the gantry frame 61 so that thesheaves 46 and 47 fit within the sheave 11 and derricking cable fastener51. The struts 42 and 43 will then rest upon the axle 12 on the top ofthe A-frame. In the illustrated embodiments, the height of the gantryfrom the road or surface 120 can be lowered from 15-7" in the extendedposition to l2'-0 in the retracted position. This 12 foot height issufiicient to clear most obstructions such as bridges, wires and thelike when the crane is being transported from one location to another inits working position. It can thus be seen that a power operatedtwo-position back-hitch gantry is obtained Which can be raised orlowered very quickly by a single operator without leaving the cab seat.Moreover, with this back-hitch type gantry, it is possible to getmaximum capacities in the upper operating position and minimum head roomor clearance in the lower position. It will be understood, however, thatthe crane can be operated with the gantry in its lowermost position butsuch maximum capacities cannot then be obtained.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

We, therefore, particularly point out and distinctly claim as ourinvention:

1. A crane comprising a supporting frame structure, an operating cab insaid supporting frame structure, a boom pivotally secured at one end ofsaid frame structure,

a back-hitch gantry at the opposite end of said frame structure, saidback-hitch gantry comprising a hinge pin, a rigid frame pivotallyinterconnecting said hinge pin and said frame structure, a pair oftelescoping strut members connected to said hinge pin and said framestructure, each of said pair of telescoping strut members comprisingupper and lower members adapted longitudinally to telescope one withinthe other, means to maintain said members parallel to each other at allpositions of telescopic adjustment; and means to lock said members inextended and retracted position thus to lock said hinge pin in a raisedand lowered position comprising locking pins for each of said pair oftelescoping strut members, an operating rod interconnecting said lockingpins for conjoint movement, cable means extending from said operatingrod to said operating cab, means within said cab to exert a pull on saidcable to release said locking pins, and spring means acting on said rodautomatically to urge said rod and thus said pins to return upon releaseof said cable.

2. The crane as set forth in claim 1 including a further frame memberpivotally mounted on said hinge pin, and sheaves mounted at the distalend of said further frame member for cooperation with a cable forraising and lowering said boom.

3. The crane as set forth in claim 1 wherein each pair of telescopingstrut members comprises lower parallel spaced guide strut members and anupper strut member slidably secured therebetween, said upper strutmember having vertically spaced apertures therein, the locking pin forsaid telescoping strut members being mounted at the top of said lowerspaced struts and being adapted automatically to enter the respectiveapertures upon raising or lowering of said upper strut member when thepull on said cable is released.

4. The crane as set forth in claim 1 wherein said means in said cab topull said cable comprises a bell-crank operating lever, said cable beingpivotally connected to one leg of said lever whereby said lever may bepivoted against the pressure of said spring means to move the pivotalconnection of said cable to said lever over center to provide a togglelock for said cable.

References Cited in the file of this patent UNITED STATES PATENTS1,533,243 Galterio Apr. 14, 1925 2,348,285 Ekbom et al May 9, 19442,689,655 Potter et al Sept. 21, 1954 2,809,756 Bannister Oct. 15, 19572,819,803 Obenchain Ian. 14, 1958 2,942,700 Parmenter et al. Jan. 28,1960

1. A CRANE COMPRISING A SUPPORTING FRAME STRUCTURE, AN OPERATING CAB INSAID SUPPORTING FRAME STRUCTURE, A BOOM PIVOTALLY SECURED AT ONE END OFSAID FRAME STRUCTURE, A BACK-HITCH GANTRY AT THE OPPOSITE END OF SAIDFRAME STRUCTURE, SAID BACK-HITCH GANTRY COMPRISING A HINGE PIN, A RIGIDFRAME PIVOTALLY INTERCONNECTING SAID HINGE PIN AND SAID FRAME STRUCTURE,A PAIR OF TELESCOPING STRUT MEMBERS CONNECTED TO SAID HINGE PIN AND SAIDFRAME STRUCTURE, EACH OF SAID PAIR OF TELESCOPING STRUT MEMBERSCOMPRISING UPPER AND LOWER MEMBERS ADAPTED LONGITUDINALLY TO TELESCOPEONE WITHIN THE OTHER, MEANS TO MAINTAIN SAID MEMBERS PARALLEL TO EACHOTHER AT ALL POSITIONS OF TELESCOPIC ADJUSTMENT; AND MEANS TO LOCK SAIDMEMBERS IN EXTENDED AND RETRACTED POSITION THUS TO LOCK SAID HINGE PININ A RAISED AND LOWERED POSITION COMPRISING LOCKING PINS FOR EACH OFSAID PAIR OF TELESCOPING STRUT MEMBERS, AN OPERATING ROD INTERCONNECTINGSAID LOCKING PINS FOR CONJOINT MOVEMENT, CABLE MEANS EXTENDING FROM SAIDOPERATING ROD TO SAID OPERATING CAB, MEANS WITHIN SAID CAB TO EXERT APULL ON SAID CABLE TO RELEASE SAID LOCKING PINS, AND SPRING MEANS ACTINGON SAID ROD AUTOMATICALLY TO URGE SAID ROD AND THUS SAID PINS TO RETURNUPON RELEASE OF SAID CABLE.